An engine generates torque by combustion pressure during an explosion stroke of a cylinder. Torque of the engine generally includes a vibration component which is proportional to the number of explosions of the cylinder per a shaft rotation due to a rapid variation of the combustion pressure. Such vibration component is transferred to a vehicle body through an engine mount and a drive shaft, which causes vibration and noise, and degrades ride comfort.
In order to solve the above-mentioned problems, an electrification vehicle including an electric motor such as an eco-friendly vehicle, and the like uses a method of actively reducing vibration generated in a powertrain using a motor, and particularly, uses a method for reducing vibration by measuring a vibration component transferred through the powertrain at the time of an explosion stroke of an internal combustion engine and applying antiphase torque for the vibration to a motor mounted in the powertrain. Here, a reference signal of the antiphase torque mainly uses a sine wave form, and a coefficient of an active filter is determined so that error between the generated vibration and the reference sine wave is the minimum. Here, since the reference signal (see 110 in FIG. 1) of the antiphase torque is different from a vibration shape (see 120 in FIG. 1) by an actual explosion of the engine, a phase difference exists between a peak of an actual vibration and a peak of the reference sine wave, which degrades performance of a vibration reduction control.